Warning: rewind(): stream does not support seeking

[acid24]

PHP version used: 7.1.0

mongo-php-library version: 1.1.0

Hello,

Using this code

/*
Uses MongoDb\GridFS\Bucket::openDownloadStreamByName($filename, array $options = []); to retrieve the file
*/
$file = $gw->retrieveFileByName('3142184dbed342fbb5ad6dc495d02405');


$metadata = stream_get_meta_data($file['stream']);
rewind($file['stream']);

I get a "Warning: rewind(): stream does not support seeking" even though stream_get_meta_data function advertises that the stream is seekable

array (
  'timed_out' => false,
  'blocked' => true,
  'eof' => false,
  'wrapper_data' => '(removed for brevity)',
  'wrapper_type' => 'user-space',
  'stream_type' => 'user-space',
  'mode' => 'r',
  'unread_bytes' => 0,
  'seekable' => true,
  'uri' => 'gridfs://mydb/fileStore.files/585bc30888461f001a7a4412',
)

This behavior causes an error in Slim framework which tries to rewind the stream in the Response object if the stream is seekable before sending it out

[jmikola]

Seeking GridFS streams is an outstanding feature, which is being tracked in PHPLIB-213.

Based on discussion in https://github.com/fruux/sabre-dav/issues/787, StreamWrapper implementations have no control over the "seekable" property of stream_get_meta_data() and always advertise themselves as seekable. Slim may want to implement similar fseek() checks that went into sabre-dav to address this (not just for GridFS but other StreamWrappers that do not support seeking).

/cc @codeguy @akrabat

[jmikola]

@acid24: We have an implementation of seeking for readable streams in #325 if you'd like to test that out. Since it's a new feature, it will not be released until 1.2.0; however, I'd be interested to hear whether it meets your needs.

In the meantime, I'm going to close this issue. Please watch PHPLIB-213 or the above PR for further updates.

[acid24]

@jmikola OK, I will test it and let you know. Thank you

[jmikola]

1.2.0-alpha1 is now tagged and includes seeking functionality for GridFS.